An aqueous solution containing 15.62 g of nickel(II) nitrate is added to an aqueous solution containing 11.51 g of sodium phosphate. A precipitate forms.

1) Predict the products (write the formula).

2) Write a balanced chemical equation.

3) Determine the limiting reactant (LR).

4) Calculate the mass of each product and the reactant in excess (XS).

3Ni(NO₃)_{2 (aq)} + 2Na₃PO_{4 (aq)} --------> Ni₃(PO₄)_{2 (s)} + 6NaNO_{3 (aq)}

Compound	3Ni(NO3)2	2Na3PO4	Ni3(PO4)2	6NaNO3
Mass (g), initial	15.62	11.51	0	0
MM (g/mol)	182.2703	163.9407	366.0229	84.9947
Moles, initial	0.08570	0.07021	0	0
Change in moles	-3x	-2x	+x	+6x
Moles, final	0	0.01308	0.02857	0.1714
Mass (g), final	0	2.144	10.46	14.57

x = 0.02856₆

Find the L.R., mass of XS reactant, and mass of N₂, CO₂, and H₂O in the following reaction.

C₂H₈N_{2 (g) +} 2N₂O_{4 (g)} --------> 3N_{2 (g)} + 2CO_{2 (g)} + 4H₂O _(g)

0.900 g 2.20 g ?g ?g ?g

Compound	C2H8N2	2N2O4	3N2	2CO2	4H2O
Mass (g), initial	0.900	2.20	0	0	0
MM (g/mol)	60.10	92.012	28.014	44.01	18.0154
Moles, initial	0.014975	0.023910		?	?
Change in moles	-x	-2x	+3x	+2x	+4x
Moles, final	0.003020	0	0.035865	0.02391	0.04782
Mass (g), final	0.1815	0	1.0047	1.0523	0.86150

x = 0.0119₅₅